Method of reenforcing cinematograph films



March 7, 1933.

A. H. ADAMS METHOD OF REENFORCING ,CINEMATOGRAPH FILMS Filed Nov. 25,1929 3 Sheets-Sheet l M m I INVENTOR 4:22.. 3 M

,L'ZZLM ATTORNEYS March 7, 1933. A, H. ADAMS METHOD OF REENFORCINGCINEMATOGRAPH FILMS Filed Nov. 25 1929 3 Sheets-Sheet 2 INVENTOR w 2441*BY A ORNEY March 7, 1933. A. H. ADAMS 1,900,681

I METHOD OF REENFORCING CINEMATO'GRAPH FILMS Filed Nov. 25 1929 3Sheets-Sheet 3 Patented Mar. 7, 1933 uurrao STATES lsaas sl PATENT orrca am-nun 1r. mats, or vonxnas, NEW voax, assr'onon' "r r. mocmmm orLONDON, ENGLAND I IETKOD 0F REENFOBCII IG CINEMATOGRAPH FILMSApplicationfiled November 25, 1929. Serial 1T0. 409,787.

This invention relates to the art of reen-- forcing cinematograph filmand has as an object the provision of suitable recnforcing stripssecured along the edges of the film and the rovision of a method ofsecuring said reen orcing strip to the film.

Other objects of the invention will be apparent to those skilled in theart from the followin' description. A preferred embodiment of theinvention will now be described. reference being made to theaccompanying drawings, wherein:

Figure 1 is a plan view of a reenforcing strip after the first operationhas been performed;

Figure 2 is a longitudinal section taken on the line 2-2 of Figure 1;

Fi re 3 is a diagrammatic view of the reen orcing strip positioned inapparatus for performing the first operation on it;

F lgure 4 is a. plan view of the film strip after one series ofapertures has been punched in it;

- Figure 5 shows apparatus for punching one series of apertures in thefilm;

Figure 6 shows apparatus for punching another series of apertures in thefilm;

Figure 7 is a p an view of the film with both series of aperturespunched in it ready for assembly with the reenforcing strips.

Fi re 8 shows apparatus for assembling the m and reenforclng strip;

Figure 9 shows apparatus for piercing the pro'ection formed on thereenforcing strip; 1 igure 10 shows the position of apparatus.

after the piercingoper'ation has been completed; v

Figure 11 shows apparatus for turning the burrs formedby the piercingoperation;

Figure 12 shows apparatus for clenching the burrs; Figure 13 shows thecompleted film and reen orcing strip; p

' Figure 14 is an enlarged bottom plan view .of the clenching burrs;

According to the preferred embodiment of the present invention, the filmand the reenforcing strips are first prepared separately andiarethereafter assembled and secured togather. For convenience indescription, the

-or even 2% may occur. This fact gives rise to a special problem whenreenforcing with metal reenforcing strips as in the referred embodimentherein, for. obvious y, since metal does not shrink with age there willbe a tendency (assuming equal lengths of metal strip and film tohave'been originally secured together) for the metal to buckle slightlyas film shrinkage occurs.

In order to minimize this tendency insofar as possible, it'isproposedbaccording to the I invention herein to assem Is the strips, andp the film in definite dimensional relationship based on the shrinkagefactor of the film. If for every given unit of length of the film at thetime of assembly a len h of reenforcing strip is selected which is sorter than the film but longer than the expected len h i of the filmafter shrinkage has occurre it will be apparent that when securedtogether in this relationship as shrinkage occurs the unit length offilm will gradually approach the length of reenforcing strip, and thenas; still more shrinkage occurs, will gradually become shorter than, thestrip. In no case, however, will the discrepancy between the two unitlengths be as great as it would be if equal lengths of film and stripwere amembled without regard to the shrinkage condition of thefilm. Byproper selectionv of the no relationship in which the two are originallyassembled the discrepancy can made very f small during the major portionof the useful life of the film.-

1% in two months but only 2% in a-year it will be apparent that if aunit of strip 1% or thereaboutsshorter thaii the film is assembledtherewith, thedisc'r'epancy in length for the major portion of the yearwill be very sli ht.

or convenience, the distance between the center of the sprocket holes orperforations may be taken as unit lengths, these holes be ing punched inthe film at standard distances during its manufacture. I

As the first step then in the preparation of the reenforcing strip,referring to Figure 1 and 3 the said strip maybe punched with preferablyarranged in a row, close to the edge of the strip and outside the, rowof; sprocket holes and their spacing being made with respect to the saidholes. Thus, in the v preferred embodiment illustrated a projection isaligned transversely with the center of each sprocket hole and a secondprojection is spaced midway between the sprocket hole centers. I i J Ifdesired, an additional set of projections may also be embossed in thestrip, these projections being located inside the projections 4 andintended to secure the inside edge of the strip against displacement.Preferably the said projections are also located midway beit tweensprocket hole centers.

As illustrated in Figure 3 of the'drawings, punches 6 for forming theprojections 4 and 5 may be associated with the punch 2 in properrelationship to provide t e desired spacing. And a spring-biasedpresser-foot 7 may be associatedwith the said punches in order to holdthe work firmly 'while being punched. The projections which are formedin the strip are preferably in the form of small rounded domes asillustrated in Figures 2 and 9.

In the preparation of the film, it is desired to provide perforationssuited to receive the projections 4 and 5 of the strip, saidperforations to be located in the same relative posi tions with respectto the sprocket holes already punched as the projections occupy withrespect to the sprocket holes in the strip, although due to thedifference in unit lengths the absolute distances between perforationswill be slightly different from the distances between projections.

For convenience (referring to Figures 4 and 5) the perforations 8 may bemade first, after which (referring to Figures 6 and 7) the perforations9 may be made. The ,perforations 8 are preferably located by referenceto opposite edges of each sprocket hole.

area (Fi This may be conveniently accomplished by providing a pilotfinger 10 having beveled aces 11 which'engage the ed of the sprocketholes and thus center the forthe punching operation. After beingcentered, the film may be held by the spring-biased m presser-foot 12which holds the .film pnt il punched by the unch 13. Figure 4 shows thefilm strip after t e holes 8 have been punched.-

The perforations 9 are also preferably located by reference to'the edgesof the sprocket holes, but instead of using opposite ed es of a singlehole as previously described, ad acent edges of adjoining holes areused; pilot finger 14 (as seen in Figure 6 having inside beveled faces15 is providedw ich centers the film by engaging edges 16, 16 of thesprocket holes. After the film is centered it may-be held by thespring-biased presser-foot 17 until punched by punches 18. n this mannerit will be observed that the perforations 9 will be accurately locatedmidway between the sprockethole centers. I

;After being thus prepared the strip and film are ready for assembly.For this purpose, as illustrated in Figure 8, the two strips are fedtogether in face-to-face relationship 1n such a manner that theprojections embossed in the strip enter the perforations in the filmsuccessively. Aswillbe understood, althou h from the strip sufficientlysmal to permit the projections to center themselves in the perforationswhen engaged successively, thus causing a slight buckling of the filmbetween successive perforations. V 1

After assembly the projections are puncgures 9 and 10) byeneedle points19 which pierce the metal and nd back burrs the film perforations arespaced different y pro ections, the difference is 20, the assembled filmand strip being held meanwhile by the presser-foot 21.

Subsequently, the burrs 20 are bent outwardly by plunger 2 havingbeveled edges 23 and finally the burrs are flattened and ressed into thefilm by ressure plate 24 whic bends the outwardly ared burrs around theedges of the fihn perforations, thus firmly securing the two together.

What I claim is: p

1. The method of longitudinally reenforcing a cinematographic film stripwith a metal strip, which comprises, centering the film strip on asprocket hole and punching an aperture in line with the s rocket hole,centering the film strip on a jacent edgm of adjoining sprocket holesand punching an ap erture between the sprocket holes, punchingprojections on a reenforcing str1 corresponding to the apertures of saidfilm strip and in the same operation punching sprocket holes in saidreenforcing strip, assembling said'strips with said projections in saidapertures, piercin said projections to form burrs, and brad ingsaid-burrs to secure said strips firmly together, substantially as setforth.

' said reenforcing strip being provided with sprocket holes mating withthe sprocket holes of the film strip and rivet means securing saidstrips together at a plurality of points outside the line of saidsprocket holes and at other points within the line of the sprocketholes.

4. The method of securing a reenforcing strip to a cinematographic filmstrip which comprises forming apertures on the film strip, formingdome-shaped projectionson said reenforcing strip, positioning saidprojections in said apertures, piercing said projections to form tubularburrs extending through said film strip, spreading said burrs by aconical die, and bradding said burrs by a flat die.

5. The method of preparing a cinematographic film strip for the assemblytherewith of a reenforcing strip, which comprises, positioning saidstrip by a tapered member engaging the edges of a single sprocket hole,holdingthe strip by a spring biased presserfoot, and punching anaperture in the film in line with the hole while the strip is held bythe presser foot.

6. The method of preparing a cinematographic film strip for the assemblytherewith of a reenforcing strip, which comprises positioning said stripby a tapered memberv engaging the adjacent edges of adjoining sprocketholes, holding said strip by a spring biased presser-foot and punchingapertures in said film intermediate said holes while the strip is heldby the presser foot.

7. The method of preparing a reenforcing strip for a cinematographicfilm strip, which comprises holding said reenforcing strip by aspring-biased presser-foot and punching a sprocket hole and a pluralityof dome- -shaped projections from said strip while so sequently turningthe ends of said walls on,

the other side of the film strip to secure the reenforcing stripthereto.

9. As an article of manufacture, a flexible film strip reenforced by aflexible metal strip along its edge, said metal strip bein attached tosaid film strip by minute urrs punched out of the metal strip itselfextend,-

is further characterized by the fact that the I rivets are locatedbetween each pair of sprocket holes.

12. The article as set forth in claim 9 which is further characterizedby the fact that the rivets are located between each pair of sprocketholes, there being two rivets on the same transverse line, one near theouter edge of the strips and another near the inner 1ongitudinal edgesof the sprocket holes.

13. As an article of manufacture, a film strip reenforced on its outeredges by a reenforcing strip secured thereto by small rivets betweeneach sprocket hole, the rivets being so narrow longitudinall of the filmstrip as to permit free flexing o the. material between each pair ofsprocket holes.

14. As an article of manufacture, a film strip reenforced on its sideedges by a reenforcing strip which is secured thereto at frequentintervals by rivets, the rivets being much smaller than the sprocketholes of the strip to permit free flexing of the composite strip over asmall radius as required in projection.

In testimony whereof, I have signed my name to this specification this6th day of November 1929.

ARTHUR H. ADAMS.

